Quarkonium Polarization Fit: Applied to one p T bin in CDF data

1. Quarkonium Polarization Fit:Applied to one pT bin in CDF data Matthew Jones Purdue University B Production and Decay Meeting

2. Recent Progress • Include rapidity dependence in background • Updated integrated luminosity • Restrict cross section to |y|<0.6 • Now using MuonLoPtEfficiency version 4.4 • CMP trigger efficiency measurement • Better understanding of the meaning of • Minima seem to be parabolic – generally okay to plot contours from error matrix instead of MINOS errors. • Measure polarization in different detector hemispheres… B Production and Decay Meeting

3. Rapidity dependence of background • Background cross section previously generated to reproduce (m,pT) distribution. • The amount of background also depends on rapidity: less background at higher rapidity. • The ϒ(nS) signal yields are essentially independent of rapidity. • Measure background yield as a function of y, reject generated events to reproduce (m,pT,y) distribution in the background. • Should be incorporated into MC generation for subsequent iterations B Production and Decay Meeting

4. Integrated Luminosity • Analyzed periods 0..28 (jbmm0d,h,I,j,k,m) • Good run list: goodrun_em_mu_nosi_cmxignored_v34 • Require complete runs for accurate luminosity accounting • Triggers: • UPSILON_CMUP_CMU • UPSILON_CMUP_CMX • Dynamically prescaled versions introduced in PHYSICS_3_07_v-1 • Equivalent luminosity: • Increased by 20% compared with previous presentation. • Unclear where the previous numbers came from; the numbers printed in the old log file agree with the current numbers. • Maybe possible, in principle, to track it down… B Production and Decay Meeting

5. Restricted ϒ(nS) rapidity • The Run I cross section measured Br(ϒ(nS) μ+μ-) x • Now restricting generated and reconstructed rapidity to the same interval, |y|<0.6. • Can also consider |y|<0.8 and |y| < 0.4 for comparison. • It will also be important to compare polarization finer intervals of rapidity in case it is changing with y. CMUP+CMU/CMUP+CMX CMUP+CMX B Production and Decay Meeting

6. CMP Efficiency • Assume a negligible fake muon component, in the CMUP+CMU trigger path • Require one muon to satisfy CMUP trigger • The other is unbiased by CMP • Analyze 15° wedges separately • Parameterize as a function of pT and z position in the chamber: B Production and Decay Meeting

7. CMP Geometry B Production and Decay Meeting

8. CMP Efficiency Is this real loss of efficiency or is it because CMU has a hole at z=0? • Example: CMP wedge 4 B Production and Decay Meeting

9. CMP Efficiency • Asymptotic efficiency in all wedges: Typically about 80% B Production and Decay Meeting

10. Measured cross section Br(ϒ(nS) μ+μ-) x • Now we measure: Corrected by a factor of 0.93 for efficiency loss due to radiative effects. Same in Run I, checked with EvtGen. B Production and Decay Meeting

11. Polarization parameters • Perhaps not quite so dramatic… 3S 2S S-channel helicity 1S Collins-Soper B Production and Decay Meeting

12. Is this even possible? 0<y<0.6 -0.6<y<0 Need to understand this better… it might even be unphysical… B Production and Decay Meeting

13. The meaning of … • Previously we had pondered what it meant when = This expression is invariant under rotations. B Production and Decay Meeting

14. General proof B Production and Decay Meeting

15. The meaning of … • There is nothing wrong with large values of ε [-1,∞) • Examples: + B Production and Decay Meeting

16. Conclusions • Confidence is building, but we still need more good cross checks… • Cross section seems low now – no good explanation at this time. • Need to understand polarization measured in subdivided acceptance regions. • Other pT bins? Maybe not quite ready yet… B Production and Decay Meeting